Task engagement, cerebral blood flow velocity, and diagnostic monitoring for sustained attention.

Loss of vigilance may lead to impaired performance in various applied settings including military operations, transportation, and industrial inspection. Individuals differ considerably in sustained attention, but individual differences in vigilance have proven to be hard to predict. The dependence of vigilance on workload factors is consistent with a resource model of sustained attention. Thus, measures of attentional resource availability may predict the operator's subsequent vigilance performance. In this study, we investigated whether a diagnostic battery of measures of response to a cognitive challenge would predict subsequent sustained attention. Measures that may relate to the mobilization of resources in response to task demands include subjective task engagement and coping, and a novel psychophysiological index, cerebral bloodflow velocity (CBFV). A two-phase design was used. First, participants were exposed to a challenging battery of short tasks that elevated CBFV. Second, participants performed a 36-min vigilance task. Two subgroups of participants performed either a sensory vigilance (N = 187) or a cognitive vigilance (N = 107) task. Measures of task engagement, coping, and CBFV response to the short task battery were compared as predictors of subsequent vigilance. Both subjective and CBFV indices of energization predicted sensory and cognitive vigilance, consistent with resource theory. Structural equation modeling was used to develop a latent factor model of influences on sustained attention. It is concluded that measures of resources, conceptualized as multiple energization processes, are potentially useful for diagnostic monitoring in applied settings. Use of a diagnostic task battery in military and transportation settings is discussed, along with some potential limitations on validity of the diagnostic test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhancement of plasmid DNA transformation efficiencies in early stationary‐phase yeast cell cultures

Chemical‐based methods have been developed for transformation of DNA into log‐phase cells of the budding yeast Saccharomyces cerevisiae with high efficiency. Transformation of early stationary‐phase cells, e.g. cells grown in overnight liquid cultures or as colonies on plates, is less efficient than log‐phase cells but is simpler and more adaptable to high‐throughput projects. In this study we have tested different approaches for transformation of early stationary‐phase cell cultures and identified a method utilizing polyethylene glycol (PEG), lithium acetate and dimethyl sulphoxide (DMSO) as the most efficient. Plasmid DNA transformations using this method could be improved modestly by allowing cells to recover from the chemical treatment in rich broth before plating to selective media. Strong increases in transformation efficiencies were observed when cells were treated briefly with dithiothreitol (DTT). Tests using several different yeast strain backgrounds indicated that DTT treatment could enhance transformation efficiencies by up to 40‐fold. Evaluation of multiple parameters affecting the efficiency of the method led to development of an optimized protocol achieving > 50 000 transformants/µg DNA in most backgrounds tested. Copyright © 2013 John Wiley & Sons, Ltd.     

A SMALL-SCALE DEMONSTRATION OF CYBERNETIC TECHNOLOGY AND ITS APPLICATION TO THE AIR FORCE LOGISTICS COMMAND (AFLC) COMMAND,CONTROL, COMMUNICATION,AND INTELLIGENCE SYSTEM

Modern-day auditing represents a decision environment that is both complex and characterized by those elements of imprecise measurability addressed by fuzzy set theory. The use of fuzzy set concepts to address this problem was originally attempted by Cooley and Hicks (1983). They derived a measure of reliability, but did not place the measure in a decision context. This article provides the necessary extension and a computational approach to decision evaluation in this environment.     

A Case Study of Hardware/Software Partitioning of Traffic Simulation on the Cray XD1

Scientific application kernels mapped to reconfigurable hardware have been reported to have 10times to 100times speedup over equivalent software. These promising results suggest that reconfigurable logic might offer significant speedup on applications in science and engineering. To accurately assess the benefit of hardware acceleration on scientific applications, however, it is necessary to consider the entire application including software components as well as the accelerated kernels. Aspects to be considered include alternative methods of hardware/software partitioning, communications costs, and opportunities for concurrent computation between software and hardware. Analysis of these factors is beyond the scope of current automatic parallelizing compilers. In this paper, a case study is presented in which a simulation of metropolitan road traffic networks is mapped onto a reconfigurable supercomputer, the Cray XD1. Five different methods are presented for mapping the application onto the combined hardware/software system. An approach for approximating the performance of each method is derived through analytic equations. Our results, both analytically and empirically, show that key predictors of performance (which are often not considered in reported speedup of kernel operations) are not necessarily maximum parallelism, but must account for the fraction of the problem that runs on the reconfigurable logic and the amount data flow between software and hardware.     

Regular expression matching with input compression: a hardware design for use within network intrusion detection systems

This paper describes an optimised finite state automata based hardware design for implementing high speed regular expression matching. Automata based implementations of regular expression matching can become quite complex and if table driven can use large amounts of memory—this can be a problem for hardware based implementations, as the amount of memory available within standard Field Programmable Gate Array (FPGA) components can be quite small as compared with the amount of resources we expect to find within a software environment. This work uses an existing ‘packed array’ style of table based automata implementation, but then adds a form of input compression to group together characters that are treated identically by the automata. A hardware design for such a system has been created for use within a Xilinx Field Programmable Gate Array and tested by simulation. The design operates at a fixed scan rate of 2.0 Gbps independent of the regular expression used or the input data being scanned. The regular expression rules are first compiled by software and then loaded into the design at run time and may be updated dynamically without modification to the design. Gerald Tripp is a Lecturer in Computer Science at the University of Kent.     

Teenagers' views on the general practice consultation and provision of contraception. The Adolescent Working Group

BACKGROUND: The rate of unwanted pregnancies in adolescents in the United Kingdom (UK) is one of the highest in Europe and is a major reason for the RCGP's concern at the under-use of general practitioners' (GPs') contraceptive services by young people. AIM: To discover the attitudes of 15- to 16-year-olds to the GP consultation and contraceptive services. METHOD: Questionnaires were completed as part of an evaluation of a novel sex education programme in 30 schools in 1994, and provided the data for this study. A total of 4481 teenagers (51.6% male and 48.4% female completed the questionnaires in their classrooms under conditions of complete confidentiality. RESULTS: The median consulting rate per year was two for males and three for females. Over 60% of adolescents attended the consultation with a parent. Of the males, 27.5% 'felt that the discussion with their GP could be relayed to their parents against their wishes', as did 25.1% of the females. Other difficulties with GP appointments were identified as embarrassment (63% of females and 46% of males), difficulty getting a quick appointment (44% of both males and females), and an unsympathetic GP (32% of females and 20.5% of males). CONCLUSIONS: Adolescents identify significant factors blocking them from easy access to consultation with their GP. These included lack of trust in confidentiality, lack of staff friendliness, and delay in appointment. Consideration of how these blocks can be removed will assist in providing improved contraceptive services in primary care. General practices need to consider the above factors when providing contraceptive and other services to their teenage patients.     

Female exposure to high G: chronic adaptations of cardiovascular functions

The substrate structure-activity relationships described for the major human drug-metabolizing cytochrome P450 (P450 or CYP) enzymes suggest that the H1 receptor antagonist terfenadine could interact with CYP2D6 either as a substrate or as an inhibitor, in addition to its known ability to act as a substrate for CYP3A4. Based on this substrate structure-activity relationship, computer modeling studies were undertaken to explore the likely interactions of terfenadine with CYP2D6. An overlay of terfenadine and dextromethorphan, a known substrate of CYP2D6, showed that it was possible to superimpose the site of hydroxylation (t-butyl group) and the nitrogen atom of terfenadine with similar regions in dextromethorphan. These observations were substantiated by the ease of docking of terfenadine into a protein model of CYP2D6. Experimentally, terfenadine inhibited CYP2D6 activity in human liver microsomes with an IC50 of 14-27 microM, depending on the CYP2D6 substrate used. The inhibition of CYP2D6 was further defined by determining the Ki for terfenadine against bufuralol 1'-hydroxylase activity in four human livers. Terfenadine inhibited bufuralol 1'-hydroxylase activity with a Ki of approximately 3.6 microM. The formation of the hydroxylated metabolite (hydroxyterfenadine) in microsomes prepared from human liver and specific P450 cDNA-transfected B lymphoblastoid cells indicated that only CYP2D6 and CYP3A4 were involved in this transformation. As expected, the rate of formation was greatest with CYP3A4 (Vmax = 1257 pmol/min/nmol of P450), with CYP2D6 forming the metabolite at a 6-fold lower rate (Vmax = 206 pmol/min/nmol of P450). The two enzymes had similar KM values (9 and 13 microM, respectively). These data indicate that, as predicted from modeling studies, terfenadine has the structural features necessary for interaction with CYP2D6.     

Selectivity of peroxide‐initiated graft modification of ethylene copolymers

Experimental data on the kinetics and selectivity of peroxide‐initiated graft modification of ethylene copolymers with vinyltriethoxysilane (VTEOS) and maleic anhydride (MAn) are presented. Rate data for the VTEOS modification and crosslinking of poly(ethylene‐co‐vinyl acetate) demonstrate the controlling influence of peroxide decomposition rates. Analysis of the selectivity for grafting versus crosslinking showed considerable scope for optimization of VTEOS modifications through variation of monomer and peroxide loadings. However, the MAn system was found to be less amenable to optimization, most likely because of differences in the graft propagation cycle and radical termination preferences.     

Bioengineered flagella protein nanotubes with cysteine loops: self-assembly and manipulation in an optical trap

An E. coli flagellin protein, termed FliTrx, was investigated for use as a novel form of self-assembling protein nanotube. This protein was genetically engineered to display constrained peptide loops with a series of different thiol, cationic, anionic, and imidazole functional groups. "Cys-loop" thiol variants consisting of 6 and 12 cysteine residues were isolated in the form of disulfide-linked nanotube bundles, a novel nanomaterial. Bundles were characterized by fluorescence microscopy, transmission electron microscopy, and optical trapping.